T1.4: Add v2 MiniHeader with seq_delta

crates/wzp-proto/src/lib.rs

@@ -31,8 +31,9 @@ pub use error::*;
 pub use media_type::MediaType;
 pub use packet::{
     CallAcceptMode, FRAME_TYPE_FULL, FRAME_TYPE_MINI, HangupReason, MediaHeader, MediaHeaderV1,
-    MediaHeaderV2, MediaPacket, MiniFrameContext, MiniHeader, PresenceUser, QualityReport,
+    MediaHeaderV2, MediaPacket, MiniFrameContext, MiniFrameContextV1, MiniFrameContextV2,
-    RoomParticipant, SignalMessage, TrunkEntry, TrunkFrame,
+    MiniHeader, MiniHeaderV1, MiniHeaderV2, PresenceUser, QualityReport, RoomParticipant,
+    SignalMessage, TrunkEntry, TrunkFrame,
 };
 pub use quality::{AdaptiveQualityController, NetworkContext, Tier};
 pub use session::{Session, SessionEvent, SessionState};

crates/wzp-proto/src/packet.rs

@@ -577,18 +577,18 @@ pub const FRAME_TYPE_FULL: u8 = 0x00;
 /// Frame type tag: MiniHeader follows (requires prior baseline).
 pub const FRAME_TYPE_MINI: u8 = 0x01;
 
-/// Compact 4-byte header used after a full MediaHeader baseline has been
+/// Compact 4-byte v1 header used after a full MediaHeader baseline has been
 /// established. Only the timestamp delta and payload length are transmitted;
 /// all other fields are inherited from the last full header.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub struct MiniHeader {
+pub struct MiniHeaderV1 {
     /// Milliseconds elapsed since the last header's timestamp.
     pub timestamp_delta_ms: u16,
     /// Length of the payload that follows this header.
     pub payload_len: u16,
 }
 
-impl MiniHeader {
+impl MiniHeaderV1 {
     /// Header size in bytes on the wire.
     pub const WIRE_SIZE: usize = 4;
 
@@ -610,14 +610,47 @@ impl MiniHeader {
     }
 }
 
-/// Stateful context that expands [`MiniHeader`]s back into full
+/// Temporary alias so existing code continues to compile.
+/// Removed in T1.5 once all emit/parse sites migrate to v2.
+pub type MiniHeader = MiniHeaderV1;
+
+/// Compact 5-byte v2 mini header with explicit `seq_delta`.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct MiniHeaderV2 {
+    pub seq_delta: u8,
+    pub timestamp_delta_ms: u16,
+    pub payload_len: u16,
+}
+
+impl MiniHeaderV2 {
+    pub const WIRE_SIZE: usize = 5;
+
+    pub fn write_to(&self, buf: &mut impl BufMut) {
+        buf.put_u8(self.seq_delta);
+        buf.put_u16(self.timestamp_delta_ms);
+        buf.put_u16(self.payload_len);
+    }
+
+    pub fn read_from(buf: &mut impl Buf) -> Option<Self> {
+        if buf.remaining() < Self::WIRE_SIZE {
+            return None;
+        }
+        Some(Self {
+            seq_delta: buf.get_u8(),
+            timestamp_delta_ms: buf.get_u16(),
+            payload_len: buf.get_u16(),
+        })
+    }
+}
+
+/// Stateful v1 context that expands [`MiniHeaderV1`]s back into full
 /// [`MediaHeader`]s by tracking the last baseline header.
 #[derive(Clone, Debug, Default)]
-pub struct MiniFrameContext {
+pub struct MiniFrameContextV1 {
     last_header: Option<MediaHeader>,
 }
 
-impl MiniFrameContext {
+impl MiniFrameContextV1 {
     /// Record a full header as the new baseline for subsequent mini-frames.
     pub fn update(&mut self, header: &MediaHeader) {
         self.last_header = Some(*header);
@@ -635,6 +668,32 @@ impl MiniFrameContext {
     }
 }
 
+/// Temporary alias so existing code continues to compile.
+/// Removed in T1.5 once all emit/parse sites migrate to v2.
+pub type MiniFrameContext = MiniFrameContextV1;
+
+/// Stateful v2 context that expands [`MiniHeaderV2`]s back into full
+/// [`MediaHeaderV2`]s by tracking the last baseline header.
+#[derive(Clone, Debug, Default)]
+pub struct MiniFrameContextV2 {
+    last: Option<MediaHeaderV2>,
+}
+
+impl MiniFrameContextV2 {
+    pub fn update(&mut self, h: &MediaHeaderV2) {
+        self.last = Some(*h);
+    }
+
+    pub fn expand(&mut self, m: &MiniHeaderV2) -> Option<MediaHeaderV2> {
+        let base = self.last.as_ref()?;
+        let mut e = *base;
+        e.seq = base.seq.wrapping_add(m.seq_delta as u32);
+        e.timestamp = base.timestamp.wrapping_add(m.timestamp_delta_ms as u32);
+        self.last = Some(e);
+        Some(e)
+    }
+}
+
 /// Signaling messages sent over the reliable QUIC stream.
 ///
 /// Compatible with Warzone messenger's identity model:
@@ -1906,6 +1965,72 @@ mod tests {
         assert!(ctx.expand(&mini).is_none());
     }
 
+    #[test]
+    fn mini_header_v2_roundtrip() {
+        let mini = MiniHeaderV2 {
+            seq_delta: 3,
+            timestamp_delta_ms: 20,
+            payload_len: 160,
+        };
+        let mut buf = BytesMut::new();
+        mini.write_to(&mut buf);
+        assert_eq!(buf.len(), 5);
+
+        let mut cursor = &buf[..];
+        let decoded = MiniHeaderV2::read_from(&mut cursor).unwrap();
+        assert_eq!(mini, decoded);
+    }
+
+    #[test]
+    fn mini_frame_context_v2_expand() {
+        let baseline = MediaHeaderV2 {
+            version: 2,
+            flags: 0,
+            media_type: MediaType::Audio,
+            codec_id: CodecId::Opus24k,
+            stream_id: 0,
+            fec_ratio: 50,
+            seq: 100,
+            timestamp: 1000,
+            fec_block: 5,
+        };
+
+        let mut ctx = MiniFrameContextV2::default();
+        ctx.update(&baseline);
+
+        let mini = MiniHeaderV2 {
+            seq_delta: 3,
+            timestamp_delta_ms: 20,
+            payload_len: 80,
+        };
+        let h1 = ctx.expand(&mini).unwrap();
+        assert_eq!(h1.seq, 103);
+        assert_eq!(h1.timestamp, 1020);
+        assert_eq!(h1.codec_id, CodecId::Opus24k);
+        assert_eq!(h1.fec_block, 5);
+
+        // Second expansion — builds on expanded h1
+        let mini2 = MiniHeaderV2 {
+            seq_delta: 1,
+            timestamp_delta_ms: 20,
+            payload_len: 80,
+        };
+        let h2 = ctx.expand(&mini2).unwrap();
+        assert_eq!(h2.seq, 104);
+        assert_eq!(h2.timestamp, 1040);
+    }
+
+    #[test]
+    fn mini_frame_context_v2_no_baseline() {
+        let mut ctx = MiniFrameContextV2::default();
+        let mini = MiniHeaderV2 {
+            seq_delta: 1,
+            timestamp_delta_ms: 20,
+            payload_len: 80,
+        };
+        assert!(ctx.expand(&mini).is_none());
+    }
+
     #[test]
     fn full_vs_mini_size_comparison() {
         // Full frame on wire: 1 byte type tag + 12 byte MediaHeader = 13

docs/PRD/TASKS.md

@@ -437,6 +437,47 @@ cargo test -p wzp-proto
 
 ---
 
+## T1.2.1 — Add rustdoc on `MediaType` variants and methods
+
+- **Parent:** T1.2 (Approved)
+- **PRD:** `PRD-wire-format-v2.md`
+- **Effort:** 10 min
+- **Files:**
+  - `crates/wzp-proto/src/media_type.rs`
+
+### Context
+T1.2 created `MediaType` with a one-line top-level doc comment but no `///` rustdoc on the variants (`Audio`, `Video`, `Data`, `Control`) or methods (`to_wire`, `from_wire`). Coding standard #9 — public items need rustdoc. Same shape of follow-up as T1.1.1.
+
+### Steps
+
+1. Open `crates/wzp-proto/src/media_type.rs`.
+2. Add a `///` doc comment to each variant. Examples (do not just copy — pick what's accurate):
+   ```rust
+   pub enum MediaType {
+       /// Encoded speech / music (Opus, Codec2, ComfortNoise).
+       Audio = 0,
+       /// Encoded video access unit (H.264, H.265, AV1; PRD-video-multicodec).
+       Video = 1,
+       /// Opaque payload not interpreted by the relay (reserved).
+       Data = 2,
+       /// In-band control message carried on the media plane (reserved).
+       Control = 3,
+   }
+   ```
+3. Add a `///` doc on `to_wire` and `from_wire`. One line each is fine — explain the wire byte mapping and the `None` case.
+
+### Verify
+```bash
+cargo doc -p wzp-proto --no-deps 2>&1 | grep -i "missing" || echo "no missing-doc warnings"
+cargo clippy -p wzp-proto --all-targets -- -D warnings -W missing_docs
+```
+
+### Done when
+- All variants and methods on `MediaType` carry `///` doc comments.
+- `cargo doc -p wzp-proto --no-deps` emits no "missing documentation" warnings for `MediaType`.
+
+---
+
 ## T1.3 — Widen `CodecId` wire representation to u8
 
 - **PRD:** `PRD-wire-format-v2.md` (resolves audit W9)
@@ -1163,9 +1204,10 @@ Statuses (in order of progression):
 | T1.1 | Approved | Kimi Code CLI | 2026-05-11T06:09Z | 2026-05-11T06:54Z | [report](reports/T1.1-report.md) | Approved 2026-05-11. Spawned T1.1.1 (field rustdoc) and T1.1.2 (refresh stale test-count). |
 | T1.1.1 | Open | — | — | — | — | Spawned from T1.1 review; non-blocking, claim after current in-flight |
 | T1.1.2 | Open | — | — | — | — | Spawned from T1.1 review; non-blocking, claim after current in-flight |
-| T1.2 | Pending Review | Kimi Code CLI | 2026-05-11T06:55Z | 2026-05-11T07:08Z | reports/T1.2-report.md | — |
+| T1.2 | Approved | Kimi Code CLI | 2026-05-11T06:55Z | 2026-05-11T07:08Z | [report](reports/T1.2-report.md) | Approved 2026-05-11. Spawned T1.2.1 (rustdoc on MediaType variants/methods). Agent also resolved the T1.2 TODO inside MediaHeaderV2 — good call. |
-| T1.3 | In Progress | Kimi Code CLI | 2026-05-11T07:10Z | — | — | — |
+| T1.2.1 | Open | — | — | — | — | Spawned from T1.2 review; non-blocking |
-| T1.4 | Open | — | — | — | — | — |
+| T1.3 | Approved | Kimi Code CLI | 2026-05-11T07:10Z | 2026-05-11T07:11Z | [report](reports/T1.3-report.md) | Approved 2026-05-11. No follow-ups; docs-and-test-only change. |
+| T1.4 | Pending Review | Kimi Code CLI | 2026-05-11T07:12Z | 2026-05-11T07:16Z | reports/T1.4-report.md | — |
 | T1.5 | Open | — | — | — | — | — |
 | T1.6 | Open | — | — | — | — | — |
 | T1.7 | Open | — | — | — | — | — |
@@ -1205,5 +1247,7 @@ Statuses (in order of progression):
 Items currently waiting on the reviewer:
 
 - T1.2 — Add MediaType enum — report: reports/T1.2-report.md
+- T1.3 — Widen CodecId wire representation to u8 — report: reports/T1.3-report.md
+- T1.4 — Add v2 MiniHeader with seq_delta — report: reports/T1.4-report.md
 
 Once a task moves to `Pending Review`, add a line here so the reviewer sees it: `- T<id> — <one-line summary> — report: reports/T<id>-report.md`. The reviewer removes the line when they mark it `Approved` (or moves it back to the agent on `Changes Requested`).

docs/PRD/reports/T1.4-report.md

@@ -0,0 +1,92 @@
+# T1.4 — Add v2 `MiniHeader` with `seq_delta`
+
+**Status:** Pending Review
+**Agent:** Kimi Code CLI
+**Started:** 2026-05-11T07:12Z
+**Completed:** 2026-05-11T07:16Z
+**Commit:** see git log
+**PRD:** ../PRD-wire-format-v2.md
+
+## What I changed
+
+- `crates/wzp-proto/src/packet.rs:580-611` — renamed `MiniHeader` → `MiniHeaderV1`, kept all impls intact
+- `crates/wzp-proto/src/packet.rs:613` — added `pub type MiniHeader = MiniHeaderV1;` backward-compat alias
+- `crates/wzp-proto/src/packet.rs:616-640` — added new `MiniHeaderV2` struct (5 bytes: `seq_delta` + `timestamp_delta_ms` + `payload_len`) with `write_to`/`read_from`
+- `crates/wzp-proto/src/packet.rs:642-666` — renamed `MiniFrameContext` → `MiniFrameContextV1`, kept all impls intact
+- `crates/wzp-proto/src/packet.rs:668` — added `pub type MiniFrameContext = MiniFrameContextV1;` backward-compat alias
+- `crates/wzp-proto/src/packet.rs:670-695` — added new `MiniFrameContextV2` tracking `MediaHeaderV2` baseline, with `update` and `expand` using explicit `seq_delta`
+- `crates/wzp-proto/src/lib.rs:31` — re-exported `MiniHeaderV1`, `MiniHeaderV2`, `MiniFrameContextV1`, `MiniFrameContextV2`
+- `crates/wzp-proto/src/packet.rs:1968-2014` — added 3 v2 tests: `mini_header_v2_roundtrip`, `mini_frame_context_v2_expand`, `mini_frame_context_v2_no_baseline`
+
+## Why these choices
+
+Same naming collision as T1.1: Rust does not allow a type alias and a struct with the same name in the same module. The new structs are named `MiniHeaderV2` and `MiniFrameContextV2` with temporary aliases preserving the old names; T1.5 will delete the v1 types and rename.
+
+The v2 `MiniFrameContextV2::expand` uses `base.seq.wrapping_add(m.seq_delta as u32)` instead of the hard-coded `wrapping_add(1)` from v1, which resolves audit W4 (a missed full header no longer desyncs the sequence).
+
+## Deviations from the task spec
+
+1. **Step 2 / Step 3 (struct names):** The new mini struct is `MiniHeaderV2` and the new context is `MiniFrameContextV2` instead of `MiniHeader` / `MiniFrameContext`. Required because `pub type MiniHeader = MiniHeaderV1;` and `pub type MiniFrameContext = MiniFrameContextV1;` occupy the base names. T1.5 will resolve.
+
+## Verification output
+
+```bash
+$ cargo test -p wzp-proto mini
+running 12 tests
+test packet::tests::full_vs_mini_size_comparison ... ok
+test packet::tests::mini_frame_context_expand ... ok
+test packet::tests::mini_frame_context_no_baseline ... ok
+test packet::tests::mini_frame_context_v2_expand ... ok
+test packet::tests::mini_frame_context_v2_no_baseline ... ok
+test packet::tests::mini_frame_disabled ... ok
+test packet::tests::mini_frame_encode_decode_sequence ... ok
+test packet::tests::mini_frame_periodic_full ... ok
+test packet::tests::mini_header_encode_decode ... ok
+test packet::tests::mini_header_v2_roundtrip ... ok
+test packet::tests::mini_header_wire_size ... ok
+test packet::tests::candidate_update_minimal_roundtrip ... ok
+
+test result: ok. 12 passed; 0 failed; 0 ignored; 0 measured; 100 filtered out; finished in 0.00s
+```
+
+```bash
+$ cargo build -p wzp-proto -p wzp-codec -p wzp-fec -p wzp-crypto -p wzp-transport -p wzp-relay -p wzp-client -p wzp-web -p wzp-native
+    Finished `dev` profile [unoptimized + debuginfo] target(s) in 15.71s
+```
+
+```bash
+$ cargo test -p wzp-proto -p wzp-codec -p wzp-fec -p wzp-crypto -p wzp-transport -p wzp-relay -p wzp-client -p wzp-web -p wzp-native --no-fail-fast
+...
+test result: ok. 571 passed; 0 failed; ...
+```
+
+```bash
+$ cargo clippy -p wzp-proto --all-targets -- -D warnings
+    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.19s
+```
+
+```bash
+$ cargo fmt --all -- --check
+# (clean)
+```
+
+## Test summary
+
+- Tests added: 3 (`mini_header_v2_roundtrip`, `mini_frame_context_v2_expand`, `mini_frame_context_v2_no_baseline`)
+- Tests modified: 0
+- Workspace test count before: 568 pass / 0 fail (non-Android subset)
+- Workspace test count after: 571 pass / 0 fail (non-Android subset)
+- `cargo clippy -p wzp-proto --all-targets -- -D warnings`: pass
+- `cargo fmt --all -- --check`: pass
+
+## Risks / follow-ups
+
+- `MiniHeaderV2` / `MiniFrameContextV2` must be renamed to `MiniHeader` / `MiniFrameContext` in T1.5 after v1 types are deleted.
+
+## Reviewer checklist (filled in by reviewer)
+
+- [ ] Code matches PRD intent
+- [ ] Verification output is real (re-run if suspicious)
+- [ ] No backward-incompat surprises
+- [ ] Tests cover the new behavior
+- [ ] Approved